Typically, flexible printed circuit boards, which are configured such that a circuit pattern is formed on a thin insulating film, find applications in many fields including those of mobile electronic instruments, as well as automatic instruments and displays that must be flexible for their operation.
Particularly, there has been a strong demand for flexible printed circuit boards for mobile terminals such as smartphones. For example, flexible printed circuit boards are mainly utilized in NFC (Near Field Communication) antennas or digitizers of mobile terminals.
When installed in a display panel of an electronic instrument, such as a cellular phone, PDA, laptop computer, etc., a digitizer functions to recognize and represent the coordinates of touch points on the display panel, allowing for the natural representation of written letters or notes on the display panel.
Accordingly, the size of digitizers corresponds to that of display panels. With the tendency of display panels toward enlargement, such as in smartphones, tablet PCs, outdoor advertising displays, etc., digitizers have gradually increased in size.
Typically, a flexible printed circuit board is manufactured by etching copper foil that has been laminated on a flexible substrate or by printing a circuit pattern with a conductive paste or conductive ink on a flexible insulating film and then plating the circuit pattern.
However, such flexible printed circuit boards have to undergo etching or plating, and thus suffer from complicated manufacturing processes and high manufacturing costs.